This invention relates to transfer printing and more particularly to a transfer material and a method of coloring the surface of an article by using the transfer material, as well as an apparatus suitable for use in carrying out the method.
Transfer printing by the use of a transfer head or pad has been widely used for printing a design on the surface of an object. U.S. Pat. No. 3,967,021 discloses a transfer printing method which employs a transfer material comprising a design layer including the design to be transfer-printed, a pair of adhesive layers between which the design layer is laminated, and a substrate layer supporting the three laminated layers. The two adhesive layers are heat-sensitive and activatable within different temperature ranges.
When the design is to be transferred to the transfer pad, the transfer material is heated to a temperature within one of the two temperature ranges so that one of the adhesive layers is activated to cause the design layer to be transferred to the transfer pad, and when the design layer is to be transferred from the pad to an article to be transfer-printed, the temperature drops within the other of the temperature ranges so that the other of said adhesive layers is activated to cause the design layer to be transferred from the pad surface to the surface of the article.
To carry out the above method it is necessary that the two steps should be conducted either in two different chambers the temperatures inside which are maintained within the above-mentioned respective ranges, or separately at a certain time interval, that is, first at a first temperature within one of the two temperature ranges and after a time interval at a different temperature within the other of the temperature ranges.
In either case, the process is time-consuming and not suitable for mass production. Moreover, since the article is heated in the process, it must be heat-resistive such as ceramics.
In order to overcome the above-mentioned disadvantages there was proposed in Japanese Patent Application No. 54-103653 a transfer printing method in which a transfer material comprising a layer of wax and a design layer of heat-sensitive adhesive ink is used so that the design layer is transferred by a transfer material to the surface of an article to be printed. Since the heat-sensitive ink remains active only while it is being heated, it is necessary that the article should be kept heated when transfer printing is conducted. This requires much time and labor.
Accordingly, it is one object of the invention to provide a transfer material which is suitable for use in transfer printing a colored design on articles made of various kinds of materials.
Another object of the invention is to provide such a transfer material as aforesaid which enables a simpler and easier method of coloring the surface of an article than if known transfer materials are used.
Another object of the invention is to provide a method of producing a colored design on the differently contoured surfaces of articles made of different kinds of materials by using the transfer material of the invention.
The technique of transfer printing is in wide use for coloring ceramic ware. Broadly, there are known three methods of coloring ceramic ware. One method (I) involves applying glaze on the surface of unglazed ceramic ware, firing the ware at about 1300.degree. C., transfer printing a colored design on the glazed surface of the ware and again firing the ware at about 800.degree. C. to 1200.degree. C. Another method (II) involves transfer printing a colored design on the surface of unglazed ceramic ware, firing the transfer-printed ware at about 500.degree. C. to 700.degree. C., applying glaze on the colored surface of the ware and then firing the ware at about 1300.degree. C. A third method (III) involves applying a mixture of glaze and a synthetic resin or resins on the surface of unglazed ceramic ware, transfer printing a colored design on the applied layer of the mixture, and then firing the ware at about 1300.degree. C.
The method of transfer printing disclosed in Japanese Patent Application No. 54-103653 above referred to can be used in either of the above-mentioned three methods of coloring ceramic ware. With this method of transfer printing, however, the ceramic ware must be heated prior to the step of transfer printing and kept at the required elevated temperature when the colored design is transferred from the transfer material to the surface of the ceramic ware. This requires much time and labor. Moreover, methods I and II require a heating step in addition to the above-mentioned firing steps, with resulting increase in the energy cost.
Another object of this invention is therefore to provide a method of producing a colored design on the surface of ceramic ware by using the transfer material of the invention.
Another object of the invention is to provide such a method as mentioned above which enables production of a multi-colored design on the surface of ceramic ware without loss of details or fidelity of the design and without requiring much time and labor and at a low energy cost.
An additional object of the invention is to provide a machine suitable for carrying out the method of the invention.
The invention will be described in detail with reference to the accompanying drawing.